Coherence resonance in an atmospheric global circulation model.

Numerical evidence is presented of a coherence-resonant behavior, induced on an atmospheric global circulation model by a white (in time and space) additive Gaussian noise with amplitude A << 1 . Intermediate A values enhance the spatiotemporal regularity of vortical patterns that contribute to the intra-annual variability of the atmospheric component of the climate. Only weak patterns (those appearing in the summer hemisphere) become ordered by noise.